python - 什么是类字节对象

Question

在 Python 3.6 中，base64.b64encode() 函数需要“一个类似字节的对象，而不是 str”。

与普通字符串相对的类字节对象的示例是什么？

Answer 1

任何逻辑上存储字节序列的东西都符合条件。这包括实际的 bytes 类型、bytearray、mmap.mmap、array.array('B')、 etc. str 在Python 3中是文本类型；字符没有以指定的编码存储，因此不能直接将它们用作原始二进制数据；它们必须用特定的编码显式编码。

有关技术定义，请参阅 Python 3 glossary :

An object that supports the Buffer Protocol and can export a C-contiguous buffer. This includes all bytes, bytearray, and array.array objects, as well as many common memoryview objects. Bytes-like objects can be used for various operations that work with binary data; these include compression, saving to a binary file, and sending over a socket.

Some operations need the binary data to be mutable. The documentation often refers to these as “read-write bytes-like objects”. Example mutable buffer objects include bytearray and a memoryview of a bytearray. Other operations require the binary data to be stored in immutable objects (“read-only bytes-like objects”); examples of these include bytes and a memoryview of a bytes object.